Context of use as a factor in determining the usability of in-vehicle devices

In recent years, the issue of usability of in-vehicle devices has received growing attention. This is in line with the increase in functionality of these devices, which has been accompanied by the introduction of various new interfaces to facilitate the user–device interaction. The complexity and diversity of the driving task presents a unique challenge in defining usability: user interaction with in-vehicle devices creates a ‘dual task’ scenario, in which conflicts can arise between primary and secondary driving tasks. This, and the safety-critical nature of driving, must be accounted for in defining and evaluating the usability of in-vehicle devices. It is evident that defining usability depends on the context of use of the device in question. The aim of this review therefore is to define usability for in-vehicle devices by selecting a set of criteria to describe the various factors which contribute to usability in this specific context of use.